I bought a new rear end with disc brakes, and I need to figure out how to put that in my car, a 91 Firebird Formula. And also Im wondering what the best manual Transmission is for my car. Its a 305 TBI. Im no mechanic, and I dont have a TON of experience with this sort of thing. My questios are:

1. Best MT for my Firebird
2. How I would swap the rearend. I have the entire rearend, swaybar and all. I need to get like bushings and such, so what would I need there too?

Thanks in advance for all of your help!!

 

Welcome to TGO.

1) Best OE is an 88+ world class T-5.
2) I'm sure if you search, you'll find a step-by-step for the rear swap. It's relatively easy and straightforward. Perhaps a shop manual or Chiltlon's should be a purchase. Sway bars are generally paired so you might consider using the one currently on your car. New sway bar bushing and endlinks would be good (on the front as well). Your master should be ok. You'll need to replace the proportioning valve for best braking preformance, and, of course, there's the e-brake issue. If the new rear has a different gear ratio, you'll need to swap the drive and/or driven gears in the trans to make the speedo read correctly. Check the following link toward the bottom for more info (I'm assuming this is a 10-bolt rear):

https://www.thirdgen.org/forums/tran...-10-bolts.html

 

The rear end is off of another third gen. Would I still need to worry about the ebrake and proportioning valve? And since its off a third gen, should I use its or my sway bar?

 

Yes, if you're going from drum to disc as I assumed you were. I'd use the sway currently on your car so that you'll be running a matched set.

JamesC

 

I agree with james completely. If your going to disk from drum i would recommend swapping the prop valve also. The main thing in the swap to worry about is to make sure the T valve where the single brake line splits into two is disconnected before dropping the rear. Swapping a rear is a direct unbolt the parts and bolt the new ones up. WHile its out i would reccomend replacing all bushings also, and maybe replacing your fuel pump while your under there with a walbro one since they like to crap out on TBI cars since there not that great, and if your planning any future mods along the way its almost a must. the stocker can only keep up with so much.

As for the tranny what future mods are you looking at? If a 350 is down the line somewhere you might want to look into a stronger manuel tranny like the t56, but if your keeping a 305 and not doing a whole lot of mods a WCT-5 are good.